Method for the elimination of foam in paper manufacture and the product thereof



Patents New. 17, 1931 HAROLD Bu RAFQON, 015 M 1 inan, massaonusnr'rs, Assrenon no r.

t me i FOLD POE CORPORATION, A CORPORATION OF MASSACHUQETTS no Drawing. Application filed June 29,

My invention broadly concerns and has as its object a new and useful method for the reduction, elimination, prevention, or alteration of foam by the use of starch, and by the 5 use of starch in conjunction with adjuvants. It more particularly concerns and has as its object a method for the reduction, elimination, prevention, or alteration of the foam met with under certain conditions in the in manufacture of paper; and it also concerns and has as its object the paper produced when this method is applied. Moreover it concerns and has as its further object the betterment of paper machine operation under is certain conditions and the improvement of h the paper made thereunder, as will be set forth in'the detail below.

Whereas adjuvants of various kinds are within the scope of m invention, 1 especially 2o refer to inorganic adguvants, and more especially to the generic group known as salts, particularly to salts partly or freely soluble, and of such salts, more particularly to salts 0%! aluminum, as for example aluminum sulp ate.

My invention in its referred embodiment," therefore, relates to t e use of starch alone or in conjunction with alum, for the reduction, elimination, prevention, or alteration of foam in paper manufacturing under certainconditions, and to the paper thus made.

Such conditions exist in some cases in connection with the use of a certain type of. fillers, especially those which are acid soluble, particularly alkaline earth metal compounds, and more particularly those alkaline earth metal compounds, as oxides, hydroxides, car-" bonates, or basic modifications of these, or compounds or mixtures of one or more of these, such as are-insoluble or substantially insoluble in water. Of these, however, certain ones to which I more specifically refer are calcium carbonate, especially in the form of lime mud such as that produced in the causticizing process, and calcium carbonate filled paper disclosed in my AGTUEE AND THE 1927. Serial No. 202,458.

and magnesium basic carbonate used in the United States Patent No. 1,595,416 of August 10 1926, and calcium carbonate and magnesium hydroxide, disclosed. in my United State iPatent No. 1,415,391 of May 9, 1922, and used in the filled paper disclosed in my United States Patent No. 1,598,104 of August 31, 1926. Of course I refer to the fillers mentioned in this para-- graph not only in their chemically pure form but also in their commercially produced form containing such impurities as may occur in such commercial products, and also when present with other material so that they constitute only a part, either major or minor, of the whole. It should he stated that any given filler of the type referred to is not necessarily of a uniform particle size; nor

are the average particle sizes of the individual fillers necessarily alike, as some of the fillers of the type referred to have relatively coarse grain particles, whereas others are much more finely divided, and some are so finely divided that they may be said to approach or he in the colloidal condition.

There are cases where paper can he made with the type of fillers referred to without foam but the reasons for the absence of foaming in these cases have not yet been complete ly worked out, and in these cases, of course, my invention is not applicable. In other cases, however, the manufacture of paper containing the type of fillers referred to is attended with so much foaming as to render the paper produced foam marked, and indeed at times to render the paper manufacturing operation itself impracticable, and it is to such cases that my invention is directed.

This foaming has been sometimes the chief factor which has prevented fillers of'the type referred to from being used on a commercial scale. The presence of a certain amount of foam may be considered as normal in paper manufacture and such foam is usually successfully controlled by well known means. as

Of course the amount of foam varies in paper manufacture and the amount of air incorporated into the pulp in the various parts of the process, through agitation, air leakage 1n pumps, and other means influences the amount of foam somewhat, as is well recognized. The foam which occurs in the cases which I am describing, however, is greater in amount than normal, and so persistent and diflicult to break that. it cannot be overcome by the usual chemical means or mechanical instrumentalities for combatting foam in paper manufacture, such as by the use of ordinary anti-foam'oils or compounds, introduced into the process withor after the addition of the ingredients of the paper, or by the use of jets, showers, sprays, employing water, steam, or compressed air, or other devices at the headbox or slices or inlet of the paper machine, or over the machine wire, or at or in the dandy roll, and hence this foam is very injurious. This foam adversely affects the formation of the 'paper, produces spots in the paper which reoperation.

duces its commercial value if it does not indeed render it unmerchantable, makes the paper machine difficult to regulate, and is extremely objectionable in many other respects both from the standpoint of the quality of the paper produced and of the difficulties introduced into the manufacturing This foam, although existent to a certain extent during the beating and subsequent stages of the paper making process, does not become especially harmful until the paper machine is reached, and at this point the foam vwhich has alread formed, or which now forms, collects, an travels along with the pulp on the wire of the paper machine. The paper made while such foam exists as described above contains many foam marks, in some cases-where the foaming cond'tions are particularly bad -enough litera touch one another throughout the entire sheet.

In an endeavor to determine the cause of the persistent foam, as experimentation on paper machines of commercial size can be carried on only at very great expense, I attempted to reproduce analogous conditions on a small scale. To this end the apparatus described immediately below was constructed which I have called a bubbler cell: into one end, -of a glass tube a proximately 2 inches in diameter and 3 inc es long, acnehole rubber stopper was inserted andover the other end of this tube a porous diaphragm, as of 2 layers of fine mesh cloth, was wired'close to the end. -This gave a device. into which compressed air could be introduced through the hole in the rubber stopper, and which caused the airthus intro duced'fto issue out as streams of 'fine bubbles through the porous diaphragm. A cylindrior by similar cal jar of about half litre capacity with a mouth about 2%, inches in diameter was ob- I tained and the bottom out off, leaving an open making-a tight joint. The combination of tube and ar was used in a vertical position, bottom end of jar uppermost. An apparatus was thus obtained which was in effect a glass cylinder with a porous bottom through which could be introduced compressed a1r. Liquids, or solids in liquid suspension, could be placed in the cylinder in the space above the diaphragm, and be subject to the compressed air coming through the diaphragm in streams of fine bubbles, which bubbled up through the liquid in the cylinder. Bubbles, or foam, could thereby be formed on the surface of the liquid.

On experiment, I found that to a considerable extent this phenomenon of persistent bubbles which had been existent in some cases in the actual paper manufacturing operation with filler of the type referred to could be reproduced on a test scale with the bubbler cell. I found that with certain fillers which give little orno trouble on the paper machine, as clay, bubbleswere formed having surfaces which were quite clean and clear and which broke quickly, but with fillers of the type referred to, the bubble surfaces were not clean but were coated with the filler and the volume and persistency of foam produced in such cases was much greater than when, for instance, a clay suspension of the same concentration was used.

These observations led me to the con- 'clusion that the extraordinary persistence of able for the purpose. Starch, in gelatinized form, acted upon the water suspension of the'filler of the type referred to, in such a way that the individual articles appeared to gather in flocks, and a though the identity of the individual particles was not lost (as could be seen under a microscope) this flocculation seemed to revent the individual particles from entermgthe bubble surfaces. .Obser-' vation of the filler suspension in the bubbler cell before and after the addition of starch showed that by the addition of the starch the bubble surfaces had been cleared from the armoring filler, and thus broke easily and quickly.

This I confirmed in a large scale paper machine experimental run in which starch was employed in the heater in connection with fibre and filler of the type referred to, the same furnish previously without the starch havingresulted in excessive foaming. The results this time showed that the armored bubble effect had been almost or completely eliminated, or at least showed that whatever had caused the large amount of persistent foam had been almost or completely eliminated, and that the paper could be run with very little foam; and also that such foam as did form could be substantially all broken down by the foam killing instrumentalities ordinarily employed at' the wet end of a paper machine.

1 do not know at present exactly the mechanism of the action of gelatinized starch on fillers of the type referred to, by which it changes the amount and kind of foam formed in some cases when these fillers are used in the paper making process. I am not certain whether it be by the effect of opposite electric charge, or by direct combination, or by other means; but there is some evidence that the starch effects a direct combination with the filler in question, whether. it be, however, by chemical combination or by absorption, is a point which is not yet known. A filler, for instance, calcium carbonate and magnesium hydroxide, such as I disclose in my United States Patent No. 1,415,391 of May 9, 1922, when treated in a water sus pension with gelatinized starch, fiocculates. If this flocculent mass be washed a number of times with water, with intermediate settlings and decantations, until the final wash water gives no test for starch with an iodine solution, and then the washed flocculent mass beviewed under a microscope, it will be seen that the mass on treating with iodine solution is stained a deep blue indicating the presence of a starch-filler complex of some sort.

Moreover, if a suspension of the calcium carbonate and magnesium hydroxide mentioned in the preceding paragraph be treated with gelatinized starch, settled, and the supernatant liquid decanted, and this decanted liquid be used to treat another sus pension of calcium carbonate and magnesium hydroxide, and the process repeated, it is possible finally to exhaust'the supernatent liquid so that it. eventually apparently has most if not all of its filler flocculating prop erties removed, thereby again indicating the formation of some complex (an association whether chemical, physical or both) with the I filler whereby the starch, or that which gives the starch its fiocculating property, is removed from the solution. Further evidence to the same effect is adduced from the ob- 'servation that under any given set of conditions, other things being equal, the more calcium carbonate and magnesium hydroxide used in a paper making furnish, the more starch there is required to control the foam completely.

"As a result of a careful study of several more experimental runs made on a paper machine along similar lines, I found that although starch did have a very beneficial effect on running paper with thetype of filler referred to, nevertheless there was a tendency for what few stra bubbles might come down with the pulp as it travelled on the machine wire, to collect at the dandy roll, to accumulate gradually, and finally to get on to the pulp web beyond the dandy roll, thereby causing a few foamspots in the paper.

I, therefore, continued my experiments with the bubbler cell in an. endeavor to find materials which could be used as adjigvants with the starch to remove the defect above noted. After considerable research, I discovered that certain materials, notably salts,

particularly of aluminum, for example alum, gave promise when used with starch in connection with the type of fillers referred to;

although it should be noted that the use of alum-alone, i. e., without starch, did not result in the removal or diminution of the ar mored bubble effect in the bubbler cell, nor appreciably effect foaming conditions on the paper machine in cases where, with the type of fillers above referred to, excessive foaming was experienced. The use of alum even with the starch, however, seemed to be contrary to ordinary chemical reasoning in the cases of those fillers of the type referred to which contained a carbonate radicle. Thisis because the alum in contact with such fillers produces carbon dioxide in the form of gas bubbles, which additional bubbles would be expected to cause ratherthan to prevent foam. As a matter of fact while the addition of alum in" alum with the type of filler referred to and this run showed conclusively that the use of an adjuvant, as alum, with the starch had a markedly beneficial effect. What few stray bubbles had been present when starch had beenvused without alum were now practically eliminated. Furthermore the running qualities of the stock on the paper machine were distinctly better; and, also, the use of the alum had the further advantage of producing in the paper stock a feel more nearly use like the pa furnishes t er stock of, ordinary clay paper an had the furnish when the starch alone was used without the alum- This would not be expected as the reaction of the stock was on'the alkaline side of the neu-' I tral point,

and the peculiar feel of regular paper making stocks containing clayis ordinarily attributed to the acid condition of I I these stocks. This improvementin the feel t io of the stockdue to the addition of the alum enabled the beater men and machine tenders 1 accustomed to running clay furnished papers more easily; to handle the beating, jordaning, I I and machlningof the paper madewith the on the filler type of the "filler referred to. g The carbon di oxide gasliberated bythe action ofthe alum of thetype referred'to which in fthis instance contained a carbonate radicle,

passed off harmlessly'anddid not cause'a per vsi stent foam. Itis apparentthen that-the use of ialumwith the starchin conjunction with the ifillers of the type referred to rep' 1 resents an important advance in, the manufactureof this type of paper. v I

, I am well awarethatstarch has been used;

- fact that alum has been'u'sed to cut down in paper making for a 'great' many years,

afiecting agent. I amwell aware alsoof the I vfoam,particularly that foam which is thought to have its origln in the rosin size, but as I have stated previously, I have found that alum alone, without starch, is of no service in affecting the foam under the specific con ditions herein described. I also know that starch has been used in conjunction with alum in paper making,- but in most of these cases,

starch has been used independently for purd known as the colloidally soluble or gelatinous poses set forth above in this paragraph, an the alum has been used merely for the regular well known paper making services that alum renders, such'as precipitatin the rosin size, increasing the retention an the like,

and if alum has been used to interact with the starch it has not been used for the purpose I use it, nor used under conditions where m invention is intended or adapted for use. I believe my use of starch, or starch and alum,

to be wholly new as I have been unable to discover eithenby an exhaustive search of the literature, or throu h personal contact with the industry, that in the papermaking art anyone has hitherto known that starch or starch in combination with alum acts with or on the type of fillers referred to, in a way which makes possible, by the 'reduction, elimination, prevention, or alteration of the foam, the running of type of fillers, which withoutgthe starch orwithout the starch and alum, would in some cases be rendered commercially impossible commercial paper with this or at least not feasible. This representsa very great practical step in advance and W111 be of great economic importance, as it rene rs whose employment has hitherto in some A'simple method, of practicing my inventionis to introduce the fibrous materials, the

filler of the type referred to, together with the starch or starch and alum into the beater, or other similar or compounding or ordisintegrating or, treating machine. This furnish is then given the usual treatment, and

run oil on the paper machine in the regular manner. My invention, however, is not con fined to this particular method, as it also in-- cludesthe addition of starchor starch and alum to zone or more ofthe other ingredients of the furnish at any other convenient point and alum are both used,

other ingredients, by steps or stages if detire amount of the starch or the starchand the alum atone time, and of course, here, as above, where starch and alum'a're both used. they need not necessarily be added at the same time or point. 7

Starch in the condition in which it ordi-v narily occurs in water. For my purpose, however, it is necessary to convert such starch 1nto what 15 condition before it becomes efiective, except of course in those cases where a modified starch is used which already gives a colloidal solution with water without further preparation. There are a number of methods of con- (2) The action of a solution of alkali, as

sodium hydroxide. on starch in the cold;

(3) Attrition of starc'h as by grinding in a ball mill whereby the outer skin of the starch granule is ruptured or otherwise bro ken, and gelatinization' of such starch then takes place in the cold.

In the practice of my invention, the gelatcommerce, is a white p0w- 'dery material, substantially insoluble in cold ,ders usable certain desirable inexpensive fill beensubjectto the restrictions imposed by the presence of excessive and persistent vfoam. t

mixing sired, instead of by the addition of the en I inization of'thestarch by heat in the pres ence of a suflicient amount of water is a convenient method. A satisfactory way is to mix the starch thoroughly with water of a 5 temperature below that of the gelatinization point of the starch in question, heat the mixture until gelatinization takes place, and although not necessary, the heating may be carried almost or to the boiling point if desired. Agitation may be conveniently employed. The gelatinized starch solution may then be cooled before use if desired. This solution of gelatinized starch is the ordinary way in which I introduce gelatinized starch into the paper making process.

Although the preparation of the starch as above with water is a simple method of accomplishing gelatinization, the scope of my invention includes the admixture of the starch prior to, during, or after its gelatinization with various of the other materials with which it may be subsequently used, and its introduction with them into the process. It also includes the introduction of the gelatinized starch into the process in dry or in nonaqueous form, alone or irrcombination with various other materials. .Moreover it also includes the introduction of starch in the process in which the starch isto be employed, and the'conversion of such starch into gelatinous form during the practice of such process.

However the introduction of previously gelatinized starch I in dry form mentioned above is not intended to include previously 35 gelatinized starch which has been dried with heat in contact with fibre and/or filler prior to its use in the furnish. This is the form in which any starch would exist which might fortuitously be present, usually in relatively small amounts, in any of the broke or reworked papers either uncoated or coated which might be used in the furnish. Such previously gelatinized starch, dried with heat in contact with fibre and/or filler, is not reconverted to any substantial degree, under the conditions obtaining in the stock preparation process, to the desired colloidal gelatinous condition, and is thus substantially ineffective in the prevention of foam.

myself to the use of any particular kind of starch, as I have found various kinds of starch, or mixtures of starches, or materials of starchy nature, suitable for my purpose; but inasmuch as in the United States corn starch is normally the cheapest kind of starch, that is the starch which I commonly find it advantageous to use. Moreover, I do not restrict myself to the use of ordinary, that is, what is known as the unmodified starches, as my invention includes also the use of starches which are modified in varying degrees, or in various manners, or are combined There are many kinds of starch, and in the practice of my invention I do not restrict with one or more other constituents as for modified starch or combined starch, is within the'scope of my invention.

Moreover in the use of a salt of aluminum I do not intend to restrict myself to the sulphate, as other aluminum salts may be used. If alum, however, be used, I may avail myself of any type of alum, whether acid, normal or basic, as any of the sulphates of aluminum or double salts known as alums are suitable. However, in practice, because of its cheapness and convenience, the salt of aluminum which I find. it advantageous to use is ordinary hommercial aluminum sulphate, commonly known as alum. This may be procured in the hydrous or anhydrous form as is most convenient, and may be. used in any suitable way, such for example as a ,solid, usually in-powdered form, or in solution, all such methods being-comprehended within the scope of my invention. Moreover, the alum used need not be in the chemically or commercially pure condition but may be introduced-in conjunction with other materials which may be present merely as impurities with the alum. or which may be introduced designedly or fortuitously with the alum.

The ingredients ordinarily used in paper making are fibrous materials, fillers, sizes, coloring matters, and the like, and all such ingredients may be used in conjunction with the starch or starch and alum within the scope of my invention. .Any of the ordinary fibrous materials are suitable, according to the type of paper desired, and moreover other fillers may be used .in conjunction with the fillers of the type referred to. Inasmuch,

however, as the reaction of the stock is on the alkaline side of the neutral point, sizes which depend for their efficacy upon the production and maintenance of an acid condition in the paper stock, such as for instance rosin size when used in the customary manner, are not suitable for use, and moreover, the coloring matters used are preferably those resistant to alkaline conditions.

There are some cases where paper made with the type of fillers referred to, either as a filling or coating constituent, or both, is

reused in the paper making process. Such papers may be those known to the trade as old papers or old waste papers or waste papers in any form, or returned trimmings or damaged paper or the like, or they may be ,the broke, that is, the partially made, the

imperfect, or the waste paper which accpmpanies the paper making, finishing, storing, packing, shipping, or the like operatlons In a paper mill, and which is reworked either in the same or some other mill. Such papers are sometimes reworked by themselves vand I Calcium carbonate and added in broken down or in pulp form in the paper making process, being treated or cooked in some cases with or without chemicals and washed it desired,-this reworking meaning to include the process of deinking if such is practiced or of bleaching or of both deinking and bleaching,-or sometimes they are added directly to the other paper making ingredients in the beater or similar or other mixing or disintegrating or treating or compounding machine, and broken up directly therein. a

The reuse in paper making of such papers as referred to in the preceding paragraph involves the introduction of a certain amount of the type of filler referred to into the paper making therein. Where there is introduced into the paper making process such papers originally containing some of the type of fillers referred to, the amount of which'filler compared with the total furnish is so small that any such filler present is decomposed substantially completely by the alum or other acidic material normally present or added for such purpose,-or if not so decomposed is present only in such a quantity as to represent an insignificant percentage on the weight of the final paper, such for example as in the vicinity of a percent or less,the foam producing tendency of such small amount of such filler is substantially negligible. However where the introduction of such substantially larger 1n quantity it tends to cause in some cases the excessive and persistent foam which I have previously described. Hence the use of starch, or starch and alum for the reduction, elimination, prevention, or alteration of foam in such cases, and in the paper thus made, is within the scope of my invention. This is, of course, the case not only wheresuch papers constitute the only source of such liller introduced, but also where they constitute only one source f the introduction of such filler, other quantity or,

quantities of such filler being incorporated in As illustrative of experimental which without starch or without starch and alum gave excessive foam, but which with starch or with starch and alum gave satisfactory results, I give the three following:

Furnish agazz'ne' grade Sulphite pulp, bleached 373 Sulphite pulp, unbleached 231 Soda pul bleached 234 Reworke old magazine papers (de-' magnesium hydroxide 860 Starch (potato) inked)- process and into the paper made.

filler by such papers is F'wrmsk B-Magazim'2 grade Sulphite pulp, bleached 350 Soda pul bleached 435 Reworke old magazine papers (de inked) 600 Broke (defective paper to be reworked) 180 Calcium carbonate and magnesium vhy- In the above furnishes, the figuresrefer to pounds air dry weight in each case except that of the filler (calcium carbonate and mag- 1 nesinm hydroxide) in which case the figure given refers to pounds bone dry weight.

In regard to the question of how -much starch or starch and alum is to be used in a given case, a convenient method of arriving at what are suitable amounts to employ is to use what would probably be 'enoughat first,

for instance at least proportionately as muchas shown in furnish B, and then to reduce the quantities in successive beaters until troublesome foam first starts to make its appearance. The run may then be continued using amounts which have thus been shown to be enough to eliminate foam troubles. A suitable relation'between the amounts of alum and starch may then be arrived atin a similar manner, by keeping the starch content at its determined point and gradually reducing the alum in successive heaters till stray foam appears and the feel of the stock begins to change, and then using an amount of alum somewhat greater than the amount used when this change was noted.

The above furnishes A, B, and C, are intended as illustrative only, and of course I do not mean to restrict my invention to these furmshes, as I have found that other widely differing furnishes give satisfactory results. Nor do I mean to restrict myself to the relative proportions of fibre, filler, starch, or starch and alum, or of starch to alum used in the illustrative furnishes, as I have found varying proportions of be suitable. Moreover, the experimental tests and experimental runs on paper machines mentioned herein are merely illustrative of other experimental tests and experi mental runs madein the development ofmy invention, and my invention is not, iiif course,

restricted to the results of the tests and runs cited herein.

-Whereas I have described paper made on these ingredients to a Fourdrinier machine my invention is not limited to paper made on such machines, but

is also applicable to paper made on cylinder machines, or on any other machines or devices used for makmg paper. Moreover in the'manufacture of paper by my process it is not necessary to employ'any auxiliary ma chinery or equipment as the standard machinery or equipment is well adapted for the purpose, but of course if auxiliary machinery or e uipment is desired to be employed, it may e used with satisfactory results. F urthermore the paper made by my process may be calendered, and finished and if desired, converted by any of the processes or with any ofthe machinery and equipmentemployed for these operations.

In this specification I have advanced several theories as partial or complete explanation of various conditions and effects, such as the theory purporting to explain the persistence of'the foam obtained in some cases with the type of fillers referred to, the theory of the action of starch on these fillers and on the foam occurring therewith, and any other theory or theories herein referred to; but I wish it to be distinctly understood that the scope of my invention is independent of theory, and that my invention is not limited or affected by the above theories, or by their validity or invalidity; as the facts are, regardless of these or any other theories, that the addition of starch to a furnish run with the type of fillers referred to which gives excessive foam so alters the furnish that the foam is reduced or completely or almost completely eliminated or prevented from forming or changed to a condition in which it is easily broken down, so that satisfactory paper can be made therefrom under conditions in which that was hitherto impossible or extremely difiicult; and that the addition of starch with alum improves the results\obtained with starch alone both as to quality of paper and as to machinb operation.

When inthe specification I speak of the reduction, elimination, prevention or alteration of foam, I do not necessarily mean the absolute removal of all foam, but what I do mean, insofar as it applies to the paper in dustry, is the reduction of foam to the -point where conditions are satisfactory for practical machine operation and where satisfactory paper can be manufactured.

In the specification and claims (1) where I use the word paper I. use it in its broad sense to include products of manufacture of all types and of all weights and thiclmesses,

which contain as an essential constituent a considerable amount ofprepared organic or inorganic fibre or both and which are capable of being produced on a Fourdrinier, cylinder, or other forming, or felting, or-shaping, or molding machine; (2) where I refer to a substance as acid soluble I mean a substance which is soluble in acid and one which when left in contact with cool freshly boiled distilled water for an appreciable length of time will impart to the water a pH value of more than 7, i. e., a pH value which is on the alkaline side of the neutral point; (3) where I use the expression alkaline earth metal, I mean to include therein not only the elementsv calcium, strontium, and barium, but also magnesium; (4) where I use the word foam, I mean it to be synonymous with the word froth. j

By the expression paper stock or stock I mean an aqueous mixture of papermaking ingredients, such as is prepared in the papermaking process, at any stage of its preparation.

Where, in the claims, I use the expression subjecting paper stock as to the action of starch, or starch and an adjuvant such as alum, I mean that the starch or starch and adjuvant may be introduced into the paper stock in any of the ways and/or at any of the points indicated in this specification.

In the claims: 1) where I use the expression elimination of foam, I mean to in clude not only those cases in which the foam is ,wholly or almost Wholly eliminated. but also those 'in which the amount of I foam formed is reduced, those in which the character of the foam is so changed that it breaks with relative ease, those in which foam is prevented from forming, and also cases in which two or more of the above possibilities are operative; (2) where I use the word compound I'mean one or more compounds of the kind indicated; and (3) where I use the word adjuvant I mean one or more adjuvants.

It is to be understood, of course, that the order of steps, methods, procedure and defor the elimination of foam comprising subjecting paper stock containing acid soluble filler which stock otherwise would produce deleterious foam in paper manufacture to the action of starch.

2. In the manufacture of paper, the method for the elimination of foamcomprising subjecting paper stock containing acid soluble filler comprising calcium carbonate which ans stock otherwise would produce deleteriousfoam in paper manufacture to the action of starch.

3. Int-he manufacture of paper, the method I for the elimination of foam comprising subjecting paper stock containing acid soluble filler comprising calcium carbonate and magnesium compound which stock otherwise filler comprising calcium carbonate and magwould produce deleterious foam in paper manufacture to the action of starch.

4. In the manufacture of paper, the method for the elimination of foam comprising subjecting paper stock containing acid soluble filler comprising calcium carbonate and magnesium hydroxide wwhich stock otherwise would produce deleterious foam in paper manufacture to the action of starch.

5. In the manufacture of paper, the method for the elimination of foam, comprising subjecting paper stock containing acid soluble filler which stock otherwise would produce deleterious foam in paper manufacture to the action of starch and alum.

6. In themanufacture of paper, the method for the elimination of foam comprising subjecting paper stock containing acid soluble filler comprising calcium carbonate which stock otherwise would produce deleterious foam in paper manufacture to the action of starch and alum.

7 In the manufacture of paper, the method for the elimination of foam comprising 'sub jecting paper stock containing acid soluble filler comprising calcium carbonate and magnesium compound which stock otherwise would produce deleterious foam in paper manufacture to the action of starch and alum.

8. In the manufacture of paper, the method for the elimination of foam comprising subjecting paper stock containing acid soluble nesium hydroxide which stock otherwise would produce deleterious foam in 'paper manufacture to the action of starch and alum.

9. In the manufacture of paper, the method for the elimination of foam comprising subjecting paper stock containing acid soluble filler which stock otherwise would produce deleterious foam in paper manufacture to the action of starch in gelatinized form.

10. In the manufacture of paper, the method for the elimination of foam comprising subjecting paper stock containing acid solu-,

ble filler which stock otherwise would produce deleterious foam in paper manufacture,

to the action of starch in gelatinized form and an adj uvant adapted in association therewith to modify foam.

11. Paper, substantially 'free'from foam marks comprising paper ingredients which normally would produce deleterious foaming in the man cture of paper, and starch.

12. Paper substantially free from foam marks comprising paper ingredients which normally would produce deleterious foaming in the manufacture of paper, and starch, and an aluminum compound.

13. Paper substantially free from foam marks comprising paper ingredients including acid soluble filler which ingredients normally would produce deleterious foaming in the manufacture of paper, and starch.

14. Paper substantially free from foam marks comprising paper ingredients including acid soluble filler comprising calcium carbonate which ingredients normally would produce deleterious foaming in the manufacture of paper, and starch..

15. Paper substantially free from foam marks comprising paper ingredients including acid soluble filler comprising calcium carbonate and magnesium compound which ingredients normally would produce deleterious foaming in themanufacture of paper, and starch.

16. Paper substantially free from foam marks comprising paper ingredients including acid soluble filler comprising calcium carbonate and magnesium hydroxide which ingredients normally would produce deleterious foaming in the manufacture of paper, and starch. 1

'17. Paper substantially free from foam marks comprising paper ingredients including acid soluble filler which ingredients normally would produce deleterious foaming in the manufacture of paper,starch, and aluminum compound.

18. Paper substantially free from foam marks comprising aper ingredients including acid soluble er comprising calcium carbonate which ingredients normally would produce deleterious foaming in the manufacture 'of paper, starch, and aluminum com pound. a I t 19. Paper substantially free from foam marks comprising paper ingredients including acid soluble fillercomprising calcium carbonate and magnesium compound which ingredients normally would produce deleterious foaming in the manufacture of paper,

starch, and aluminum compound.

' 20. Paper substantially free from foam marks comprising paper ingredients including acid soluble filler comprising calcium carbonate and magnesium hydroxide which ingredients normally would produce deleterious foaming in the manufacture of paper, starch, and aluminum compound.

21. Paper substantially free from foam 7 marks comprising paper ingredients including old paper stock, acid soluble filler and starch.

22. Paper substantially free from foam marks comprising paper ingredients including old paper stock, acid soluble filler comprising calcium carbonate, and starch.

23. Paper substantially free from foam marks comprising paper ingredients including old paper stock, acid soluble filler comprising calcium carbonate and magnesium compound, and starch.

24. Paper substantially free. from foam marks comprising paper ingredients'dncluding old paper'stock, acid soluble filler comprisin calcium carbonate, magnesium 'hydroxi e, and starch.- V

- a duce deleterious foam a; marks comprising paper I 1o 34. In the manufacture of aper 'which menace I 25. Paper substantially free from foam marks comprising'paper ngredients including'old paper stock, acid. soluble filler, starch I and aluminum compound.

' 26. Paper substantially free from foam marks comprising paper ingredients including'old paper stoc acid soluble .filler comprising calcium carbonate, starch, and aluminum compound.

27. Paper substantially free from foam marks comprising aper ingredients including old paper stoc acid soluble filler com- 1 prising. calcium carbonate and. magnesium compound, starch, and aluminum compound.

28. Paper substantially free fromfoam markscomprising aper ingredients including old paper stoc acid soluble filler compnsm droxi e, starch, and aluminum .compound. 90 29. Paper substantially free from foam marks comprising paper ingredients includwith unflocculated calcium carbonate would have produced deleterious foam in the manufa'cture of paper, and flocculated calcium carbonate. I

In testimony whereof I aflix my signature.

HAROLD R. RAFTON.

calcium carbonate magnesium hy- 7 as ing sulphite pulp, soda pulp, old paper stock,

t and soluble filler comprlsmg alkaline earth metal compound, and starch.

marks comprlsingpaper ingredients includ-' ing sulphite pulp, soda pulp, old paper stock,

' acid'soluble filler-com rising alkahne earth metal compound, stare and aluminum com- 30 pound.

y 31. In the manufacture of paper, the method for the elimination of foam comprising subjecting paper stock containing acid solublefiller which stock otherwise would pro to the action of starch and an adj uvant adapted 1n association therewith to modify 32. In the manufacture of paper, the method for the elimination of foam comprising subjecting paper stock containing acid sol-,

uble filler which stock otherwise would pro- 4 duce deleterious foam in paper manufacture to the action of starch and an aluminum salt. p 33. Paper substantially free from foam cm which 30. Paper substantially free from "foam in paper manufacture with unaoctultttd acid sol u le filler would i have produced deleterious foam in the manplfatitnure of paper, andfloccula'ted acid solue er. v

stock which contains acidsolub e filler and normally would produce deleterious foam in' pa flotation 0 said acid soluble filler into the I of bubbles resent with consequent armor ng'thereof, t e improvement which compnses'flocculating said acid soluble-filler from III"

r manufacture as result of the whereby flotation of such filler into the bnb-. a

blesurfaces with consequent formation of deleterious foam is substantially prevented. 35.'-Insthe manufacture m, of a r o which contains acid soluble 7 pr sing calcium carbonate and which'normany-would produce deleterious foam in PM? manufacture result-of-t e fl o I I or com- 

